1. FIELD OF THE INVENTION
This invention relates to a clutch plate for automotive use, the clutch plate comprising a hub for mounting on a shaft, a carrier plate for a friction lining and a torsional vibration damper operative between the lining carrier plate and the hub.
2. DESCRIPTION OF THE PRIOR ART
It is known to provide clutch plates with means for absorbing torsional shock loadings and damping torsional vibration. Most commonly, the lining carrier plate is supported for limited rotation relative to the hub of the clutch plate, a number of circumferentially disposed springs being arranged to resist such relative rotation. Damping is provided by friction elements engaging the lining carrier plate.
The use of friction elements for damping has a disadvantage in that their static coefficient of friction is higher than their dynamic coefficient of friction. This means that the torque required to cause relative movement in the clutch plate to commence is higher than that required to sustain such movement, up to the point at which further movement is prevented by the springs. Vibrations up to a certain magnitude are not satisfactorily damped.